1. Field of the Invention
The present invention relates to pulse signal generators.
2. Description of the Related Art
In the fields of automatic controls, and electrical and electronics equipment, a pulse signal responsive to the position or speed of a moving object or a variety of operations has been used.
An example of the pulse signal generators of this type is a rotation detector that employs an electromagnetic, light pick-up, Hall or magnetic reluctance element. The electromagnetic type, however, suffers from a low output at low speed rotations. The light pick-up type requires a broadband d-c amplifier and a dust-proof structure. The Hall or magnetic reluctance type requires a plurality of elements and an amplifier. The elements of the light pick-up/Hall/magnetic reluctance type are too sensitive to temperatures to be used in the atmosphere that can have a large temperature change.
Consequently, where the rotation detector is used to detect the rotary speed or position of a crank or cam shaft of a car, it is impossible to detect very low to high speed rotations. In addition, it is necessary to provide an interface circuit for an engine control module. Moreover, the rotation detector is not suitable for use in automobiles where it can be exposed to temperature changes or noise. Furthermore, it is difficult for the rotation detector to make a stop/move decision (whether the car is at rest or in motion) when the power is on.
Japanese patent application Kokai Nos. 2000-101400 and 2000-101401 disclose pulse signal generators that employ a magnetic element wire for producing a large Barkhausen jump to detect very low to high speed rotations. These pulse signal generators are able to resolve the above problems but need improvements for use in automobiles. That is, they must be easy to assemble or connect to equipment that uses the generated pulse signal or high in the S/N ratio or load capacity according to applications.
Accordingly, it is an object of the invention to provide a pulse generator capable of resolving the above problems and being suitable for practical applications.
According to the invention there is provided a pulse signal generator which comprises a detecting assembly using a magnetic element wire capable of producing a large Barkhausen jump to generate a series of electric pulses; and a waveform shaping circuit integrated with the detecting assembly so as to shape a waveform of the electric pulses to output a pulse signal.
According to embodiments of the invention, the waveform shaping circuit has a pair of threshold values. The detecting assembly further comprises a wire bobbin surrounding the magnetic element wire, a coil wound around the wire bobbin, and a pair of output terminals connected to both ends of the coil, the magnetic element wire, the coil, and the output terminals being integrated with the bobbin as a unit. The waveform shaping circuit is mounted on a waveform shaping circuit board, which has a pair of input terminals for connection to the output terminals of the coil. The output terminals extend toward the waveform shaping circuit board for direct connection with the waveform shaping circuit. The detecting assembly and the waveform shaping circuit are embedded in the outer case.